But while he's believed to have shed as much as 8kg, the 29-year-old says he feels lighter mentally after writing and promoting his recently released book Piri: Straight Up.

Weepu was “skeptical” about the merits of the project at first, but said it had turned out to be a “great journey”.

“I have people tweet me quite a bit saying they enjoyed the book and they've got a better understanding of who I am, which is really positive.

"It's been really good talking about, basically what I get criticised for every year [my weight]. It's just the person I am, I don't really care what other people think ... I think I'm a pretty straightforward person.”

And it's that approach he hopes to bring to the All Blacks' attack against the Springboks and he said the side had learned some important lessons against Argentina.

“We talked at halftime that everyone was panicking. At the back end of the week everyone was really excited about doing things, wanting to be here, wanting to be there, basically trying too hard.

“We said if we do our core roles and do what we talk about during the week without any complications we'll be better, and I think we saw that in the second half. We narrowed everything down, tried to be more basic with everything.”